1. Field of the Invention
The present invention relates to a field emission lamp and, more particularly, to a field emission lamp capable of increasing the uniformity and the intensity of the light output therefrom by installing a mesh cathode portion to increasing the number of electron emitting points thereof, and of forming an anode portion on a portion of the inner surface of the outer shell thereof.
2. Description of Related Art
A conventional field emission lamp comprises: a transparent outer shell, an anode portion, a cathode portion, and a phosphor layer. The anode portion and the phosphor layer are formed on an inner surface of the transparent outer shell in sequence. The cathode portion is installed on a central position inside the transparent outer shell. Besides, the operation mechanism of the conventional field emission lamp is: electrons is emitted from the cathode portion, being accelerated by the high potential of the anode portion, then being collided with the phosphor layer formed on the anode portion. At this time, the light generated by the phosphor layer, due to the bombardment of the electrons, must passes through the phosphor layer, the anode portion, and the transparent outer shell, before being output to the exterior of the conventional field emission lamp, for the purpose of illumination.
Moreover, in the conventional field emission lamp, the surface of the cathode portion is a continuous flat surface, such as a flat curving surface of a clavate-shaped cathode portion. When the number of the anode electron emitting points needs to be increase, the area of the field emission surface of the cathode portion (i.e. the surface are of the cathode portion) is required to rise, or, increasing the density of the cathode portion to emit electrons without increasing the surface area of the cathode portion. In the prior art, as the cathode portion is formed by solid metal material, the increasing of the surface area of the cathode portion results in the increasing in the weight of the cathode portion. Thus, the conventional field emission lamp is easily over-weighted, making the supporting pillar thereof be easily broken.
Therefore, a field emission lamp capable of increasing the uniformity and the intensity of the light output therefrom by installing a mesh cathode portion to increasing the number of electron emitting points thereof, and of forming an anode portion on a portion of the inner surface of the outer shell thereof is required by the industry.